When a heat transfer oil circulation heating system operates in chemical, pharmaceutical, and other facilities, the heating rod must remain immersed in the medium for extended periods, and its maintenance condition directly affects system safety and service life. The following explains the key points for using the FBR-28 stainless steel explosion-proof heating rod in a Q&A format, focusing on maintenance and precautions of interest to procurement personnel.
Before installation, verify that the heating rod nameplate parameters match the design documents, including rated voltage, power, explosion-proof marking, and protection rating. The wiring cavity must be reliably grounded, and the cable entry device should compress the sealing ring to ensure explosion-proof performance is not compromised. The heating rod should be fully immersed in the heat transfer oil to avoid dry firing; an interlock protection must be provided when the liquid level falls below the heating zone. For applications using multiple rods in parallel, confirm that the branch current matches the circuit breaker setting to prevent overload.
Inspection priorities include the sealing condition of the junction box, coking on the heating rod surface, and any leakage at flange or threaded connections. If surface coking is found, it should be cleaned promptly to avoid affecting heat transfer efficiency and causing localized overheating. Also check the explosion-proof flexible conduit for damage and verify that the grounding wire is secure. It is recommended to measure insulation resistance quarterly; the cold-state value should not be lower than 20 MΩ, and trend changes should be recorded.
When insulation resistance continues to decline and cannot recover, heating power noticeably decreases, or cracks or bulges appear on the surface, the heating rod should be taken out of service and replaced. Replacement must use products of the same explosion-proof rating and specifications; the structure must not be altered or materials substituted without authorization. Discarded heating rods should be disposed of as electrical waste to avoid environmental pollution.
Some users operate at overvoltage to increase heating speed, which accelerates component aging and may compromise explosion-proof performance; others fail to retighten terminal bolts to the original torque after maintenance, resulting in increased contact resistance and overheating. The correct approach is to follow the maintenance intervals and torque requirements specified in the product manual and to retain maintenance records for traceability.
